0654.C3.2.02 — Define relative molecular mass, Mr, as the sum of the relative atomic masses. Relative formula mass, Mr, will be used for ionic compounds: past paper questions
Real questions on 0654.c3.2.02 — define relative molecular mass, mr, as the sum of the relative atomic masses. relative formula mass, mr, will be used for ionic compounds
The newest 5 of 5 written questions. Open one to see it on the real paper.
- 0973/31 · May/June 2026 · Q8a[2]
8 (a) The formula of sulfuric acid is H,SO,. Calculate the relative molecular mass M, of sulfuric acid. [A, : H, 1; 0, 16; S, 32] relative molecular Mass .......... este ..........
See it on the paper → - 0973/31 · October/November 2025 · Q6b[1]
Determine the relative molecular mass, M r , of methane, CH 4 . relative molecular mass, M r = [A r : C, 12; H, 1]
See it on the paper → - 0973/32 · May/June 2025 · Q6a(iv)[1]
Determine the relative molecular mass, M r , of ethanol. [A r : C, 12; H, 1; O, 16] relative molecular mass =
See it on the paper → - 0973/41 · May/June 2022 · Q5b[1]
Ammonium sulfate, (NH 4 ) 2 SO 4 , is made by reacting an acid with an alkali. Calculate the relative formula mass, M r , of ammonium sulfate. [A r : H, 1; N, 14; O, 16; S, 32] relative formula mass =
See it on the paper → - 0973/41 · May/June 2019 · Q8a(i)[1]
Using information in the Periodic Table on page 32, calculate the relative molecular masses of the gases nitrogen and chlorine. M r (nitrogen) = M (chlorine) =
See it on the paper →
What examiners said
A common incorrect answer was 29 (the sum of the different types of atom present) with no attempt to look at how many of each type of atom were in the formula. Familiarity with what a chemical formula represents is fundamental to chemistry and it was clear a number of candidates either did not look at the formula or did not understand it.
— Examiner report, May/June 2025, 0973/32 Q6(a)(iv) (Cambridge)
Most candidates were able to correctly calculate the relative formula mass of ammonium sulfate.
— Examiner report, May/June 2022, 0973/41 Q5(b) (Cambridge)
Some candidates realised that nitrogen and chlorine are diatomic so their relative molecular masses are twice their relative atomic masses.
— Examiner report, May/June 2019, 0973/41 Q8(a)(i) (Cambridge)
Past papers, syllabus and examiner reports © UCLES (Cambridge University Press & Assessment). Questions are matched to topics from the official syllabus. AssessPro is independent and not endorsed by Cambridge.